The present invention relates to a transformer transporting/assembling method in a transformer transported in a disassembled condition and a U-shaped iron core assembling device.
In recent years, voltage to be supplied to a transmission system increases with an increase in electric power demand. Accordingly, the capacity, size, and weight of static induction electric appliances, such as transformers, used for power transmission/transformation increase.
Transformer stations in which a transformer is installed are often located in sites with severe transport conditions, such as mountainous area or underground of urban areas. Therefore, it is necessary to significantly reduce the transportation dimension and weight of the static induction electric appliance installed in such sites.
In such a case, a disassembled transportation method capable of significantly reducing the transportation scale and weight of a product to be transported has been adopted as a transportation method of the transformer. In this method, a large capacity three-phase transformer, etc. that has already been produced and tested in a factory is disassembled into several components: a U-shaped iron core, yokes, coils, and the like, then the components are housed in transportation tanks specially designed for the respective components to their installation site, and the respective components are reassembled in, e.g., a clean house built at the installation site. A transformer transported using the above disassembled transportation method is referred to as “disassembled transportation transformer”. Recently, the U-shaped iron core is disassembled further into smaller parts (e.g., leg iron core and lower-yoke iron core) in order to reduce the size of components to be transported.
Conventionally, as disclosed in Patent Japanese Patent Application Laid-Open Publication No. 2004-111855, the entire content of which is incorporated herein by reference, the U-shaped iron core or U-shaped iron core that has been divided into a leg iron core and lower-yoke iron core is carried in a spare room where dehumidification and dust removal have been accomplished, taken out of a transporting tank, etc., and carried in an assembling room such as a clean house where dehumidification and dust removal have been accomplished using a heavy device, etc. In the assembling room, the U-shaped iron core and U-shaped iron core tank housing the U-shaped iron core are assembled.
The tank housing the U-shaped iron core is carried out from the assembling room by a heavy machine, etc. and temporarily installed outside the assembling room. After that, at least two heavy machines are used to hoist up/down the U-shaped iron core tank using a wire, etc. while controlling the attitude of the U-shaped iron core tank so as to erect the tank.
However, there exist the following problems in the above example.
For example, an iron core of a large capacity three-phase five-leg transformer is constituted by four U-shaped iron cores. Thus, it is necessary to assemble the four U-shaped iron cores at the installation site after the assembling room of the clean house has been built up. In general, it takes about 7 days to complete the assembly of one U-shaped iron core. In the space of a conventional assembling room where the U-shaped iron core is assembled, it is possible to assemble at most two U-shaped iron cores simultaneously, in general. In this case, it takes about 14 to 17 days to complete the assembly of all the U-shaped iron cores. Thus, it takes more time to install the entire transformer than in the case of a general disassembled transportation transformer where the iron core is transported in the form of the U-shaped iron core by the time length required for assembling the U-shaped iron core at the installation site.
Further, the above work schedule is applicable to only a case where the weather is stable. For example, it is necessary to open the roof of the assembling room when the iron core is carried in the assembling room, so that the carry-in work cannot be performed in the case of rain, delaying the installation.
Further, carry-in of the leg iron core and the yoke iron core and carry-out of an erection tank in which the U-shaped iron core is housed and erected need to be performed using a tow truck. Hoisting up/down of the iron core by a tow truck needs to be performed in both the assembling room and the spare room. The tow truck is parked in the intermediate portion between the assembling room and the spare room and, there, the hoisting up/down of the leg iron core and yoke iron core is performed in a state where the arm of the tow truck is extended in an inclined manner. Thus, a tow truck with large hoisting capacity is required. The rental fee, etc., of such a tow truck with large hoisting capacity is high, and there is no other way but to rent a tow truck whose per-unit time rental fee is high in order to assemble the U-shaped iron core, causing increase in cost.
Further, at least two heavy devices, etc. are required in order to erect the U-shaped iron core or the tank housing the U-shaped iron core. More concretely, at least one 200 ton-class heavy device and one 100 ton-class heavy device are required, requiring a large installation space and a high rental fee, which increases cost.